USB: at91_udc wakeup event updates

This updates the AT91 UDC driver's handling of wakeup events:

 - Fix a bug in the original scheme, which was never updated after
   the {enable,disable}_irq_wake() semantics were updated to address
   refcounting issues (i.e. behave for shared irqs).

 - Couple handling of both type of wakeup events, to be more direct.  The
   controller can be source of wakeup events for cases like bus reset
   and USB resume.  On some boards, VBUS sensing is also IRQ driven.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>